docs: def hwm14(Z, latitude=0, longitude=0, day=0, seconds=0, 
            geomagnetic_disturbance_index=4):
      r'''Horizontal Wind Model 2014, for calculating wind velocity in the
      atmosphere as a function of time of year, longitude and latitude, and 
      earth's geomagnetic disturbance. The model is described in [1]_.
      
      The model no longer accounts for solar flux.
      
      Parameters
      ----------
      Z : float
          Elevation, [m]
      latitude : float, optional
          Latitude, between -90 and 90 [degrees]
      longitude : float, optional
          Longitude, between -180 and 180 or 0 and 360, [degrees]
      day : float, optional
          Day of year, 0-366 [day]
      seconds : float, optional
          Seconds since start of day, in UT1 time; using UTC provides no loss in
          accuracy [s]
      geomagnetic_disturbance_index : float, optional
          Average daily `Ap` or also known as planetary magnetic index.
          
      Returns
      -------
      v_north : float
          Wind velocity, meridional (Northward) [m/s]
      v_east : float
          Wind velocity, zonal (Eastward) [m/s]
          
  
      Examples
      --------
      >>> hwm14(5E5, 45, 50, 365)
      (-38.64341354370117, 12.871272087097168)
  
      Notes
      -----
      No full description has been published of this model; it has been defined by
      its implementation only. It was written in FORTRAN, and is accessible
      at http://onlinelibrary.wiley.com/store/10.1002/2014EA000089/asset/supinfo/ess224-sup-0002-supinfo.tgz?v=1&s=2a957ba70b7cf9dd0612d9430076297c3634ea75.
      
      F2PY auto-compilation support is not yet currently supported.
      To compile this file, run the following command in a shell after navigating
      to $FLUIDSPATH/fluids/optional/. This should generate the file hwm14.so
      in that directory.
          
      f2py -c hwm14.pyf hwm14.f90
      
      The fortran .pyf signature file is included with this project, but it can
      also be re-created with the command:
          
      f2py -m hwm14 -h hwm14.pyf hwm14.f90
      
      If the module is not compiled, an import error will be raised.
      
      No patches were necessary to either the generated pyf or hwm14.f90 file,
      as the authors of [1]_ have made it F2PY compatible.
      
      Developed using 73 million data points taken by 44 instruments over 60 
      years.
      
      References
      ----------
      .. [1] Drob, Douglas P., John T. Emmert, John W. Meriwether, Jonathan J. 
         Makela, Eelco Doornbos, Mark Conde, Gonzalo Hernandez, et al. "An Update
         to the Horizontal Wind Model (HWM): The Quiet Time Thermosphere." Earth
         and Space Science 2, no. 7 (July 1, 2015): 2014EA000089. 
         doi:10.1002/2014EA000089.
      '''
      # Needed by hwm14
      os.environ["HWMPATH"] = os.path.join(os.path.dirname(__file__), 'optional')
      try:
          import optional.hwm14
      except: # pragma: no cover
          raise ImportError(no_gfortran_error)
      ans = optional.hwm14.hwm14(day, seconds, Z/1000., latitude, longitude, 0, 0, 
                 0, np.array([np.nan, geomagnetic_disturbance_index]))
      return tuple(ans.tolist())